1. Field of the Invention
This invention relates to an apparatus for breaking up soil turned by a bottom plow. In particular, the invention relates to an apparatus for breaking up adhesive soils, such as those having a high clay content, turned by a bottom plow, such as a bidirectional moldboard plow with an adjustable tilting mechanism. The invention also relates to a combination of a reversible bottom plow and an apparatus for turning and breaking up such adhesive soils.
2. Description of Related Art
A plow is essentially a wedge that is dragged through the soil by a draft animal or a farm vehicle, such as a tractor. The plow cuts away the top layer of the soil and turns over that layer. In this manner, it is possible to incorporate harvest remains, expose pests and weeds to the weather, and to prepare the soil for planting and to retain water.
In order to turn and break up soil, moldboard and rotary disc plows are already known and used. Disc plows are made up of a series of rotary concave discs mounted individually and supported by a frame. Their soil penetrating ability is primarily due to their weight although it is also affected by the vertical and horizontal positions of the discs. Because the discs are rotary, they allow bidirectional operation solely by reversing the direction of their disc faces. Nevertheless, disc plows are limited by the cutting width of their discs.
A conventional moldboard plow comprises a share, a unidirectional moldboard, and a landside. The share is a blade-like portion of the plow which makes a substantially horizontal cut into the soil and frees the top layer of the soil. The moldboard is attached to the share and lifts and turns this layer of soil. Moldboard plows also require a landside, e.g., a protective heel or wear plate or similar structure, to compensate for the lateral force on the moldboard and to control depth. The landside is fixed to the side of the moldboard and slides along the vertical wall of the furrow. It thrusts the moldboard on to turn the layer of soil.
Moldboard plows cause a layer of soil to be cut and rolled e.g., turned, by the curved, tilted arrangement of the moldboard. There are various designs of moldboard for different speeds of plowing, width of cut, and types of soil. The bodies of moldboard plows also occasionally require a disconnecting device for uneven ground or ground with stumps, rocks, hard strips, or other obstructions.
Plows with multiple moldboards are common. Such plows commonly comprise moldboards that are then fastened to supports. A plurality of these supports are fastened to a moldboard frame. Because they do not leave the soil without cutting and turning it and are not limited by their cutting width, moldboard plows are generally preferred over disc plows.
Nevertheless, moldboard plows usually have a single set of moldboards that can only turn the soil in one direction. For example, see U.S. Pat. No. 3,559,745 to Thompson et al. Thus, it has been necessary in the past to plow a field in strips or in a series of parallel furrows which has left the surface of the soil uneven.
Reversible moldboard plows have been developed to avoid this problem. They permit an operator, who has completed plowing a strip of soil, to turn the plow around, reverse the direction of the moldboards, and continue to plow, turning the soil in the same direction as before. This allows an operator to plow a field from one end of a field to the other end and leaves the soil more even, i.e. leaves the soil surface level.
There are at least two types of reversible plows currently in use. First, there is the two-way or roll-over plow. This type of reversible plow is described in U.S. Pat. No. 4,207,951 to Wilcox et al., which is incorporated hereto by reference. Second, there is the bidirectional moldboard plow. This type of reversible plow and an example of this type of plow, a bidirectional moldboard plow with an adjustable tilting mechanism, are described in U.S. Pat. No. 4,942,928 to Gomez, which is also incorporated herein by reference.
The roll-over type of reversible plow carries two sets of moldboards, and each set is designed to turn the soil in an opposite direction. When an operator has plowed one strip of soil, the plow is turned and the moldboards are rolled over, so that the opposite set of moldboards engages the soil. In this manner, the operator may continue to plow a field and turn the soil in the same direction. This plow, however, possesses at least three disadvantages. First, it's weight is greatly increased by the necessity of carrying a second set of moldboards. Second, it is less stable because of its higher center of gravity. Third, complicated equipment and powerful motors are often required to roll the sets of moldboards over.
The bidirectional moldboard plow avoids these disadvantages. By using a single set of moldboards, there is a reduction in the weight of the plow and a lowering of its center of gravity. Moreover, because the moldboards are bidirectional, they need only be pivoted to cut the soil in either direction, i.e., in opposite directions.
Bottom plowing turns the soil to a relatively deep depth, e.g., in a range of about 1.333 to 1.5 feet (0.406 to 0.457 m). Bottom plows are intended to thoroughly turn the soil and cause uncleared plant material, such as corn stalks, to be buried deep in the soil to decompose and, thereby, to replenish nutrients. This deep plowing also thoroughly aerates the soil, which can be especially important in soils possessing a high clay content.
A bidirectional moldboard plow has a share-like edge at each side of the bidirectional moldboards. Further, a landside is fixed to each side of the trailing face of the moldboard. By reversing the bidirectional moldboard, the plow cuts the soil with an alternative share-like edge and an alternative landside is placed in the furrow. Moreover, if the plow is equipped with an adjustable tilting mechanism, such as that disclosed in U.S. Pat. No. 4,942,928 to Gomez, the angle at which the share-like edge of the moldboard engages the soil can be varied. By varying this angle, the depth of the bottom of the furrow cut by a moldboard from the surface of the soil may also be varied.
Despite these improvements, the ability to plow a field from one end to the other and obtain an even soil surface will depend in part on the soil type. For example, if the soil has significant adhesive qualities, e.g., high clay content, such as is found in many southeastern, southern, and southwestern states in the United States of America; soil that has been turned by a bottom plow may not break up, but instead, may form clumps or clods of soil. Therefore, bottom plowing in such soils will often leave fields uneven and unprepared for planting. Moreover, the uneven soil surface in such fields can hinder the operation of other farm equipment. Further, if large clumps or clods of turned, but unbroken, soil remain in the fields, one of the primary purposes of bottom plowing, namely to bury uncleared plant material, will not be accomplished. It is often necessary, therefore, to break up these clumps or clods of soil in some other manner before the soil can be planted or any further work in preparation for planting can be accomplished.
We recognized the need for an apparatus for use with bottom plows which would break up the clumps or clods of soil and achieve a better leveled soil surface after plowing. Further, it is desirable that this apparatus is suitable for use with reversible bottom plows, such as bidirectional moldboard plows with adjustable tilting mechanisms. An improved bottom plow that is a combination of a reversible bottom plow and a soil breaking apparatus is also recognized as particularly useful.